Yellow disazo dyes for cotton and process of making them.



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AUGUST LEUBOLD LASKA, OF OFFENBACHON-THE-MAIN, GERMANY, ASSIGNOR TOCORPORATION OF CHEMISCHE FABRIK GRIESHEIM-ELEKTRON, 0F FRANKFURT-oN-"rHn-riam, GERMANY.

YELLOH DISAZO DYES FOE COTEIDN'AND PROCESS OF MAKING TI -IEM.

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To all whom it may concern Be it known that I, AUGUsT LnoroLo LAsKA,doctor of philosophy, chemist, and a citizen of the German Empire, andresident of ()tl'enbach-on-the-lvlain, in the Grand Duchy of Hesse,(with the post-oliice address Wilhelmsplatz 18,) Germany, have in ventednew and useful Improvements in Yellow Disazo Dyes for Cotton andProcesses of Making Them, of which the following is a specification.

My invention relates to the production of new azo dyestufl's which maybe obtained by combining the diazo compound of a metasubstitutedbenzidin .with two molecular in'oportions of anl-aminophenyl-5-pyrazolone-B-carboxylic acid or with two molecularproportions of 1-nitrophenyl-5-pyrazolone-3-carboxylic acid and reducingthe nitro groups to ainido groups. These dyestuffs, having probably thefollowing formula coon

\/ co-N onm'i n \N=N H 1 0 (icon wherein R means C1 or CH are, when dry,orange to red powders, soluble in concentrated sulfuric acid with ayellowish red to red tone, yield upon reduction with stannous chloridand hydrochloric acid a meta-substr tuted benzidin and al-aminophenyliamino-5-pyrazolone-3carboxylic acid, and dye cotton yellowto reddish yellow shades, which are turned into a brilliant orange andred, respectively, bythe diazotation on the fiber and the combinationwith beta-naphthol.

Under the term metasubstituted benzi- Specification of Letters Patent.Application filed August is, 1913.

sulfid in 100 parts Patented Apr. 2S, 1914. Serial No. 785,017.

din I include meta-substitution products of benzidin of the formula:

wherein R means C1 or CH,.

In order to illustrate the new process more fully, the followingexamples are given, the parts being by weight:

Example chlorobenzidin (NI-I :Cl-l:3) are dis solved'in 250 parts of hotwater and 22.8 parts of hydrochloric acid of 20 B., fil" tered, ifnecessary, and after cooling down with ice diazotized with aconcentrated s0- luz tion of 3.45 parts of'sodium nitrite. The terazosolution, thus obtained, is poured into a solution, cooled with ice; of12.5 parts of l-meta-nitrophenyl-5-pyrazolone-3-carboxylic acid in 7parts of caustic soda lye of Be. and 200 parts of water, to which aconcentrated solution of 15 parts of calcinated soda is added. hen thecombination is complete, the mixture is heated to and maintained for anhour at 80 after addition of a solution of 36 parts of sodium of water.Then the dye stuff, thus obtained, is precipitated with common salt. Thesame dyestufi' is formed by combining the aforesaid tetrazo solution insoda alkaline solution with1-meta-'aminophenyl-5-pyrazolone-3-carboxylic acid. It forms, when dry,an orange powder, soluble in concentrated sulfuric acid witha-yellowisli red tone. It dyes cotton yellow shades turning into abrilliant orange after the diazotation and combination with betanaphthol.

Example II: 10.6 parts of meta-.tolidin are dissolved in 200 parts ofwater and 27 parts of hydrochloric acid of 20 B. and, after cooling withice, diazotized with a solution of 6.9 parts of sodium nitrite. The

I: 6.3 parts of n1eta-mcta -di-.

tetra-Z0 solution, thus obtained, is poured in a a solution, cooled withice, of 25 parts of l meta nitrophenyl 5 pyrazolone 3 carboxylic acid,23 parts of caustic soda lye of 35 Be. and 30 parts of calcinated sodain 200 parts of water. When the combination is complete, the mixture isheated to and stirred for an hour at 60 after addition of a solution of72 parts of sodium sulfid in 150 parts of water. Then the dyestud, thusobtained, is precipitated with common salt. The same dyeslufi' isobtained by combining the tetrazotized meta-tolidin with-1 metaaniinophenyl 5 pyrazolone 3 carboxylic acid in soda, alkaline solution.It forms, when dry, a red powder, soluble in concentrated sulfuric acidwith a yellowish red tone. It dyes cotton reddish yellow shades turninginto a brilliant orange by the diaz0- tation and combination withbeta-naphth'ol.

By combining the l-para nitrophenyl pyrazolone-S-carboxylic acid withthe tetrazotized meta-tolidin and by reducing afterward a dyestuft isobtained,.which tor-ms,

when dry, a dark red powder, soluble in con-- centrated sulfuric acidwith a red tone, and dyes cotton also reddish yellow shades and gives ayellowish red by the diazotation and combination with beta-naphthol.

Now what I claim and desire to secure by Letters Patent is thefollowing:

1, The process of making yellow disazo dyes for cotton consisting incombining the tetrazo compound of a meta-substituted benzidin with twomolecular proportions of a l nitrophenyl 5 pyrazolone 3 carboxylic acid,and reducing the nitrogroups to amino groups.

2. As new articles the dyestufl's, which may be obtained by combiningthe tetrazo compound of a meta-substituted benzidin with two molecularproportions of a l-nitrophenyl-5-pyrazolone-i-carboxylic acid andreducing the nitro groups to amino groups,

which dyestufis are, when dry, orange to red powders, soluble, inconcentrated sulfuric acid with a yellowish red to red tone, yieldingupon reduction with stannous chlorid and hydrochloric acid ameta-substituted benzidin and a l-aminophenyl-4l-amino-5-pyrazolone-3-carboxylic acid, and dye cotton yellow to reddish yellowshades, tcsnin;

4 oss tee into a brilliant orange to red, by the diazo tation on thefiber and the combination with to amido groups, which dyestufiis, havingin form of free acid probably the formula:

coon N= N-cr I coon form, when dry, orange powders, soluble inconcentrated sulfuric acid with a yellowish red tone, yielding uponreduction with stannous chlorid and hydrochloric acid metadichlorobenzidin and a 1-aminophenyl-4-amino-5-pyrazolone-3-carbo:-tylic acid, and dye cotton yellow shades,turning into a brilliant orange by the diazotation on the fiber and thecombination with bcta-naphthol.

In testimony, that I claim the foregoing as my invention, 1 have signedmy name in presence of two witnesses, this thirty-first day of July,1913.

AUGUS'ILEOPOLD LASKA.

Witnesses: I

Purse LAUTENsonLAoER,

FRITZ Dlison.

